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Replace executable’s fingerprint in place

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* admin/merge-gnulib (GNULIB_MODULES): Add memmem-simple.
(AVOIDED_MODULES): Add memchr.
* configure.ac (HAVE_PDUMPER): AC_SUBST it, too, for use in makefiles.
* lib/Makefile.in (libgnu_a_OBJECTS): Add fingerprint.o.
* lib/fingerprint.c: New file.
* lib/memmem.c, lib/str-two-way.h, m4/memmem.m4: New files,
copied from Gnulib.
* lib/fingerprint.h: Rename from src/fingerprint.h.
* lib-src/make-fingerprint.c: Include limits.h, sys/stat.h,
fingerprint.h, intprops.h, min-max.h.
(SSIZE_MAX): New macro, if not already defined.
(main): Without -r, Replace the fingerprint in the input file
instead of generating a fingerprint.c.
* lib/Makefile.in (libgnu_a_OBJECTS): Add fingerprint.o.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* src/Makefile.in (HAVE_PDUMPER, MAKE_PDUMPER_FINGERPRINT):
New macros.
(temacs$(EXEEXT)): Use them to replace the fingerprint instead
of precalculating it.
(mostlyclean, ctagsfiles1): Do not worry about fingerprint.c.
This commit is contained in:
Paul Eggert 2019-04-14 16:31:24 -07:00
parent 661f44946d
commit 5c2f94a182
12 changed files with 881 additions and 61 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
admin/merge-gnulib
View file

@ -36,7 +36,7 @@ GNULIB_MODULES='
filemode filevercmp flexmember fpieee fstatat fsusage fsync
getloadavg getopt-gnu gettime gettimeofday gitlog-to-changelog
ieee754-h ignore-value intprops largefile lstat
manywarnings memrchr minmax mkostemp mktime nstrftime
manywarnings memmem-simple memrchr minmax mkostemp mktime nstrftime
pipe2 pselect pthread_sigmask putenv qcopy-acl readlink readlinkat regex
sig2str socklen stat-time std-gnu11 stdalign stddef stdio
stpcpy strtoimax symlink sys_stat sys_time
@ -47,7 +47,7 @@ GNULIB_MODULES='
AVOIDED_MODULES='
btowc close dup fchdir fstat langinfo lock
malloc-posix mbrtowc mbsinit mkdir msvc-inval msvc-nothrow nl_langinfo
malloc-posix mbrtowc mbsinit memchr mkdir msvc-inval msvc-nothrow nl_langinfo
openat-die opendir raise
save-cwd select setenv sigprocmask stat stdarg stdbool
threadlib tzset unsetenv utime utime-h

6
configure.ac
View file

@ -379,8 +379,12 @@ if test "$with_dumping" = "unexec" && test "$with_unexec" = "no"; then
fi
if test "$with_pdumper" = "yes"; then
AC_DEFINE(HAVE_PDUMPER, 1, [Define to build with portable dumper support])
AC_DEFINE([HAVE_PDUMPER], 1, [Define to build with portable dumper support])
HAVE_PDUMPER=yes
else
HAVE_PDUMPER=no
fi
AC_SUBST([HAVE_PDUMPER])
DUMPING=$with_dumping
AC_SUBST(DUMPING)

121
lib-src/make-fingerprint.c
View file

@ -25,14 +25,25 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include <limits.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sysstdio.h>
#include <sha256.h>
#include <fingerprint.h>
#include <getopt.h>
#include <intprops.h>
#include <min-max.h>
#include <sha256.h>
#ifndef SSIZE_MAX
# define SSIZE_MAX TYPE_MAXIMUM (ssize_t)
#endif
#ifdef WINDOWSNT
/* Defined to be sys_fopen in ms-w32.h, but only #ifdef emacs, so this
@ -54,41 +65,62 @@ main (int argc, char **argv)
raw = true;
break;
case 'h':
printf ("make-fingerprint [-r] FILES...: compute a hash\n");
return 0;
printf ("make-fingerprint [-r] FILE: replace or compute a hash\n");
return EXIT_SUCCESS;
default:
return 1;
return EXIT_FAILURE;
}
}
struct sha256_ctx ctx;
sha256_init_ctx (&ctx);
for (int i = optind; i < argc; ++i)
if (argc - optind != 1)
{
FILE *f = fopen (argv[i], "r" FOPEN_BINARY);
if (!f)
{
fprintf (stderr, "%s: Error: could not open %s\n",
argv[0], argv[i]);
return 1;
}
char buf[128*1024];
do
{
size_t chunksz = fread (buf, 1, sizeof (buf), f);
if (ferror (f))
{
fprintf (stderr, "%s: Error: could not read %s\n",
argv[0], argv[i]);
return 1;
}
sha256_process_bytes (buf, chunksz, &ctx);
} while (!feof (f));
fclose (f);
fprintf (stderr, "%s: missing or extra file operand\n", argv[0]);
return EXIT_FAILURE;
}
FILE *f = fopen (argv[1], raw ? "r" FOPEN_BINARY : "r+" FOPEN_BINARY);
struct stat st;
if (!f || fstat (fileno (f), &st) != 0)
{
perror (argv[1]);
return EXIT_FAILURE;
}
if (!S_ISREG (st.st_mode))
{
fprintf (stderr, "%s: Error: %s is not a regular file\n",
argv[0], argv[1]);
return EXIT_FAILURE;
}
ptrdiff_t maxlen = min (min (TYPE_MAXIMUM (off_t), PTRDIFF_MAX),
min (SIZE_MAX, SSIZE_MAX));
if (maxlen <= st.st_size)
{
fprintf (stderr, "%s: %s: file too big\n", argv[0], argv[1]);
return EXIT_FAILURE;
}
char *buf = malloc (st.st_size + 1);
if (!buf)
{
perror ("malloc");
return EXIT_FAILURE;
}
size_t chunksz = fread (buf, 1, st.st_size + 1, f);
if (ferror (f) || chunksz != st.st_size)
{
fprintf (stderr, "%s: Error: could not read %s\n",
argv[0], argv[1]);
return EXIT_FAILURE;
}
sha256_process_bytes (buf, chunksz, &ctx);
unsigned char digest[32];
sha256_finish_ctx (&ctx, digest);
@ -99,12 +131,37 @@ main (int argc, char **argv)
}
else
{
puts ("#include \"fingerprint.h\"\n"
"unsigned char const fingerprint[] =\n"
"{");
for (int i = 0; i < 32; ++i)
printf ("\t0x%02X,\n", digest[i]);
puts ("};");
char *finger = memmem (buf, chunksz, fingerprint, sizeof fingerprint);
if (!finger)
{
fprintf (stderr, "%s: %s: missing fingerprint\n", argv[0], argv[1]);
return EXIT_FAILURE;
}
else if (memmem (finger + 1, buf + chunksz - (finger + 1),
fingerprint, sizeof fingerprint))
{
fprintf (stderr, "%s: %s: two occurrences of fingerprint\n",
argv[0], argv[1]);
return EXIT_FAILURE;
}
if (fseeko (f, finger - buf, SEEK_SET) != 0)
{
perror (argv[1]);
return EXIT_FAILURE;
}
if (fwrite (digest, 1, sizeof digest, f) != sizeof digest)
{
perror (argv[1]);
return EXIT_FAILURE;
}
}
if (fclose (f) != 0)
{
perror (argv[1]);
return EXIT_FAILURE;
}
return EXIT_SUCCESS;

2
lib/Makefile.in
View file

@ -84,7 +84,7 @@ Makefile: ../config.status $(srcdir)/Makefile.in
# and building it would just waste time.
not_emacs_OBJECTS = regex.o
libgnu_a_OBJECTS = $(gl_LIBOBJS) \
libgnu_a_OBJECTS = fingerprint.o $(gl_LIBOBJS) \
$(patsubst %.c,%.o,$(filter %.c,$(libgnu_a_SOURCES)))
for_emacs_OBJECTS = $(filter-out $(not_emacs_OBJECTS),$(libgnu_a_OBJECTS))
libegnu_a_OBJECTS = $(patsubst %.o,e-%.o,$(for_emacs_OBJECTS))

66
lib/fingerprint.c Normal file
View file

@ -0,0 +1,66 @@
/* Placeholder fingerprint for Emacs
Copyright 2019 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include "fingerprint.h"
/* This random fingerprint was generated by the shell command:
shuf -i 0-255 -n 32 -r | awk '{printf " 0x%.02X,\n", $0}'
In the final Emacs executable, this random fingerprint is replaced
by a fingerprint of the temporary Emacs executable that was built
along the way. */
unsigned char const fingerprint[] =
{
0xDE,
0x86,
0xBB,
0x99,
0xFF,
0xF5,
0x46,
0x9A,
0x9E,
0x3F,
0x9F,
0x5D,
0x9A,
0xDF,
0xF0,
0x91,
0xBD,
0xCD,
0xC1,
0xE8,
0x0C,
0x16,
0x1E,
0xAF,
0xB8,
0x6C,
0xE2,
0x2B,
0xB1,
0x24,
0xCE,
0xB0,
};

0
src/fingerprint.h → lib/fingerprint.h
View file

14
lib/gnulib.mk.in
View file

@ -44,6 +44,7 @@
# --avoid=malloc-posix \
# --avoid=mbrtowc \
# --avoid=mbsinit \
# --avoid=memchr \
# --avoid=mkdir \
# --avoid=msvc-inval \
# --avoid=msvc-nothrow \
@ -111,6 +112,7 @@
# largefile \
# lstat \
# manywarnings \
# memmem-simple \
# memrchr \
# minmax \
# mkostemp \
@ -1053,7 +1055,6 @@ gl_GNULIB_ENABLED_03e0aaad4cb89ca757653bd367a6ccb7 = @gl_GNULIB_ENABLED_03e0aaad
gl_GNULIB_ENABLED_2049e887c7e5308faad27b3f894bb8c9 = @gl_GNULIB_ENABLED_2049e887c7e5308faad27b3f894bb8c9@
gl_GNULIB_ENABLED_21ee726a3540c09237a8e70c0baf7467 = @gl_GNULIB_ENABLED_21ee726a3540c09237a8e70c0baf7467@
gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b = @gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b@
gl_GNULIB_ENABLED_37f71b604aa9c54446783d80f42fe547 = @gl_GNULIB_ENABLED_37f71b604aa9c54446783d80f42fe547@
gl_GNULIB_ENABLED_5264294aa0a5557541b53c8c741f7f31 = @gl_GNULIB_ENABLED_5264294aa0a5557541b53c8c741f7f31@
gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c = @gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c@
gl_GNULIB_ENABLED_682e609604ccaac6be382e4ee3a4eaec = @gl_GNULIB_ENABLED_682e609604ccaac6be382e4ee3a4eaec@
@ -1963,6 +1964,17 @@ EXTRA_libgnu_a_SOURCES += lstat.c
endif
## end gnulib module lstat
## begin gnulib module memmem-simple
ifeq (,$(OMIT_GNULIB_MODULE_memmem-simple))
EXTRA_DIST += memmem.c str-two-way.h
EXTRA_libgnu_a_SOURCES += memmem.c
endif
## end gnulib module memmem-simple
## begin gnulib module memrchr
ifeq (,$(OMIT_GNULIB_MODULE_memrchr))

71
lib/memmem.c Normal file
View file

@ -0,0 +1,71 @@
/* Copyright (C) 1991-1994, 1996-1998, 2000, 2004, 2007-2019 Free Software
Foundation, Inc.
This file is part of the GNU C Library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, see <https://www.gnu.org/licenses/>. */
/* This particular implementation was written by Eric Blake, 2008. */
#ifndef _LIBC
# include <config.h>
#endif
/* Specification of memmem. */
#include <string.h>
#define RETURN_TYPE void *
#define AVAILABLE(h, h_l, j, n_l) ((j) <= (h_l) - (n_l))
#include "str-two-way.h"
/* Return the first occurrence of NEEDLE in HAYSTACK. Return HAYSTACK
if NEEDLE_LEN is 0, otherwise NULL if NEEDLE is not found in
HAYSTACK. */
void *
memmem (const void *haystack_start, size_t haystack_len,
const void *needle_start, size_t needle_len)
{
/* Abstract memory is considered to be an array of 'unsigned char' values,
not an array of 'char' values. See ISO C 99 section 6.2.6.1. */
const unsigned char *haystack = (const unsigned char *) haystack_start;
const unsigned char *needle = (const unsigned char *) needle_start;
if (needle_len == 0)
/* The first occurrence of the empty string is deemed to occur at
the beginning of the string. */
return (void *) haystack;
/* Sanity check, otherwise the loop might search through the whole
memory. */
if (__builtin_expect (haystack_len < needle_len, 0))
return NULL;
/* Use optimizations in memchr when possible, to reduce the search
size of haystack using a linear algorithm with a smaller
coefficient. However, avoid memchr for long needles, since we
can often achieve sublinear performance. */
if (needle_len < LONG_NEEDLE_THRESHOLD)
{
haystack = memchr (haystack, *needle, haystack_len);
if (!haystack || __builtin_expect (needle_len == 1, 0))
return (void *) haystack;
haystack_len -= haystack - (const unsigned char *) haystack_start;
if (haystack_len < needle_len)
return NULL;
return two_way_short_needle (haystack, haystack_len, needle, needle_len);
}
else
return two_way_long_needle (haystack, haystack_len, needle, needle_len);
}
#undef LONG_NEEDLE_THRESHOLD

452
lib/str-two-way.h Normal file
View file

@ -0,0 +1,452 @@
/* Byte-wise substring search, using the Two-Way algorithm.
Copyright (C) 2008-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written by Eric Blake <ebb9@byu.net>, 2008.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, see <https://www.gnu.org/licenses/>. */
/* Before including this file, you need to include <config.h> and
<string.h>, and define:
RESULT_TYPE A macro that expands to the return type.
AVAILABLE(h, h_l, j, n_l)
A macro that returns nonzero if there are
at least N_L bytes left starting at H[J].
H is 'unsigned char *', H_L, J, and N_L
are 'size_t'; H_L is an lvalue. For
NUL-terminated searches, H_L can be
modified each iteration to avoid having
to compute the end of H up front.
For case-insensitivity, you may optionally define:
CMP_FUNC(p1, p2, l) A macro that returns 0 iff the first L
characters of P1 and P2 are equal.
CANON_ELEMENT(c) A macro that canonicalizes an element right after
it has been fetched from one of the two strings.
The argument is an 'unsigned char'; the result
must be an 'unsigned char' as well.
This file undefines the macros documented above, and defines
LONG_NEEDLE_THRESHOLD.
*/
#include <limits.h>
#include <stdint.h>
/* We use the Two-Way string matching algorithm (also known as
Chrochemore-Perrin), which guarantees linear complexity with
constant space. Additionally, for long needles, we also use a bad
character shift table similar to the Boyer-Moore algorithm to
achieve improved (potentially sub-linear) performance.
See http://www-igm.univ-mlv.fr/~lecroq/string/node26.html#SECTION00260,
https://en.wikipedia.org/wiki/Boyer-Moore_string_search_algorithm,
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.34.6641&rep=rep1&type=pdf
*/
/* Point at which computing a bad-byte shift table is likely to be
worthwhile. Small needles should not compute a table, since it
adds (1 << CHAR_BIT) + NEEDLE_LEN computations of preparation for a
speedup no greater than a factor of NEEDLE_LEN. The larger the
needle, the better the potential performance gain. On the other
hand, on non-POSIX systems with CHAR_BIT larger than eight, the
memory required for the table is prohibitive. */
#if CHAR_BIT < 10
# define LONG_NEEDLE_THRESHOLD 32U
#else
# define LONG_NEEDLE_THRESHOLD SIZE_MAX
#endif
#ifndef MAX
# define MAX(a, b) ((a < b) ? (b) : (a))
#endif
#ifndef CANON_ELEMENT
# define CANON_ELEMENT(c) c
#endif
#ifndef CMP_FUNC
# define CMP_FUNC memcmp
#endif
/* Perform a critical factorization of NEEDLE, of length NEEDLE_LEN.
Return the index of the first byte in the right half, and set
*PERIOD to the global period of the right half.
The global period of a string is the smallest index (possibly its
length) at which all remaining bytes in the string are repetitions
of the prefix (the last repetition may be a subset of the prefix).
When NEEDLE is factored into two halves, a local period is the
length of the smallest word that shares a suffix with the left half
and shares a prefix with the right half. All factorizations of a
non-empty NEEDLE have a local period of at least 1 and no greater
than NEEDLE_LEN.
A critical factorization has the property that the local period
equals the global period. All strings have at least one critical
factorization with the left half smaller than the global period.
And while some strings have more than one critical factorization,
it is provable that with an ordered alphabet, at least one of the
critical factorizations corresponds to a maximal suffix.
Given an ordered alphabet, a critical factorization can be computed
in linear time, with 2 * NEEDLE_LEN comparisons, by computing the
shorter of two ordered maximal suffixes. The ordered maximal
suffixes are determined by lexicographic comparison while tracking
periodicity. */
static size_t
critical_factorization (const unsigned char *needle, size_t needle_len,
size_t *period)
{
/* Index of last byte of left half, or SIZE_MAX. */
size_t max_suffix, max_suffix_rev;
size_t j; /* Index into NEEDLE for current candidate suffix. */
size_t k; /* Offset into current period. */
size_t p; /* Intermediate period. */
unsigned char a, b; /* Current comparison bytes. */
/* Special case NEEDLE_LEN of 1 or 2 (all callers already filtered
out 0-length needles. */
if (needle_len < 3)
{
*period = 1;
return needle_len - 1;
}
/* Invariants:
0 <= j < NEEDLE_LEN - 1
-1 <= max_suffix{,_rev} < j (treating SIZE_MAX as if it were signed)
min(max_suffix, max_suffix_rev) < global period of NEEDLE
1 <= p <= global period of NEEDLE
p == global period of the substring NEEDLE[max_suffix{,_rev}+1...j]
1 <= k <= p
*/
/* Perform lexicographic search. */
max_suffix = SIZE_MAX;
j = 0;
k = p = 1;
while (j + k < needle_len)
{
a = CANON_ELEMENT (needle[j + k]);
b = CANON_ELEMENT (needle[max_suffix + k]);
if (a < b)
{
/* Suffix is smaller, period is entire prefix so far. */
j += k;
k = 1;
p = j - max_suffix;
}
else if (a == b)
{
/* Advance through repetition of the current period. */
if (k != p)
++k;
else
{
j += p;
k = 1;
}
}
else /* b < a */
{
/* Suffix is larger, start over from current location. */
max_suffix = j++;
k = p = 1;
}
}
*period = p;
/* Perform reverse lexicographic search. */
max_suffix_rev = SIZE_MAX;
j = 0;
k = p = 1;
while (j + k < needle_len)
{
a = CANON_ELEMENT (needle[j + k]);
b = CANON_ELEMENT (needle[max_suffix_rev + k]);
if (b < a)
{
/* Suffix is smaller, period is entire prefix so far. */
j += k;
k = 1;
p = j - max_suffix_rev;
}
else if (a == b)
{
/* Advance through repetition of the current period. */
if (k != p)
++k;
else
{
j += p;
k = 1;
}
}
else /* a < b */
{
/* Suffix is larger, start over from current location. */
max_suffix_rev = j++;
k = p = 1;
}
}
/* Choose the shorter suffix. Return the index of the first byte of
the right half, rather than the last byte of the left half.
For some examples, 'banana' has two critical factorizations, both
exposed by the two lexicographic extreme suffixes of 'anana' and
'nana', where both suffixes have a period of 2. On the other
hand, with 'aab' and 'bba', both strings have a single critical
factorization of the last byte, with the suffix having a period
of 1. While the maximal lexicographic suffix of 'aab' is 'b',
the maximal lexicographic suffix of 'bba' is 'ba', which is not a
critical factorization. Conversely, the maximal reverse
lexicographic suffix of 'a' works for 'bba', but not 'ab' for
'aab'. The shorter suffix of the two will always be a critical
factorization. */
if (max_suffix_rev + 1 < max_suffix + 1)
return max_suffix + 1;
*period = p;
return max_suffix_rev + 1;
}
/* Return the first location of non-empty NEEDLE within HAYSTACK, or
NULL. HAYSTACK_LEN is the minimum known length of HAYSTACK. This
method is optimized for NEEDLE_LEN < LONG_NEEDLE_THRESHOLD.
Performance is guaranteed to be linear, with an initialization cost
of 2 * NEEDLE_LEN comparisons.
If AVAILABLE does not modify HAYSTACK_LEN (as in memmem), then at
most 2 * HAYSTACK_LEN - NEEDLE_LEN comparisons occur in searching.
If AVAILABLE modifies HAYSTACK_LEN (as in strstr), then at most 3 *
HAYSTACK_LEN - NEEDLE_LEN comparisons occur in searching. */
static RETURN_TYPE
two_way_short_needle (const unsigned char *haystack, size_t haystack_len,
const unsigned char *needle, size_t needle_len)
{
size_t i; /* Index into current byte of NEEDLE. */
size_t j; /* Index into current window of HAYSTACK. */
size_t period; /* The period of the right half of needle. */
size_t suffix; /* The index of the right half of needle. */
/* Factor the needle into two halves, such that the left half is
smaller than the global period, and the right half is
periodic (with a period as large as NEEDLE_LEN - suffix). */
suffix = critical_factorization (needle, needle_len, &period);
/* Perform the search. Each iteration compares the right half
first. */
if (CMP_FUNC (needle, needle + period, suffix) == 0)
{
/* Entire needle is periodic; a mismatch in the left half can
only advance by the period, so use memory to avoid rescanning
known occurrences of the period in the right half. */
size_t memory = 0;
j = 0;
while (AVAILABLE (haystack, haystack_len, j, needle_len))
{
/* Scan for matches in right half. */
i = MAX (suffix, memory);
while (i < needle_len && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
++i;
if (needle_len <= i)
{
/* Scan for matches in left half. */
i = suffix - 1;
while (memory < i + 1 && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
--i;
if (i + 1 < memory + 1)
return (RETURN_TYPE) (haystack + j);
/* No match, so remember how many repetitions of period
on the right half were scanned. */
j += period;
memory = needle_len - period;
}
else
{
j += i - suffix + 1;
memory = 0;
}
}
}
else
{
/* The two halves of needle are distinct; no extra memory is
required, and any mismatch results in a maximal shift. */
period = MAX (suffix, needle_len - suffix) + 1;
j = 0;
while (AVAILABLE (haystack, haystack_len, j, needle_len))
{
/* Scan for matches in right half. */
i = suffix;
while (i < needle_len && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
++i;
if (needle_len <= i)
{
/* Scan for matches in left half. */
i = suffix - 1;
while (i != SIZE_MAX && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
--i;
if (i == SIZE_MAX)
return (RETURN_TYPE) (haystack + j);
j += period;
}
else
j += i - suffix + 1;
}
}
return NULL;
}
/* Return the first location of non-empty NEEDLE within HAYSTACK, or
NULL. HAYSTACK_LEN is the minimum known length of HAYSTACK. This
method is optimized for LONG_NEEDLE_THRESHOLD <= NEEDLE_LEN.
Performance is guaranteed to be linear, with an initialization cost
of 3 * NEEDLE_LEN + (1 << CHAR_BIT) operations.
If AVAILABLE does not modify HAYSTACK_LEN (as in memmem), then at
most 2 * HAYSTACK_LEN - NEEDLE_LEN comparisons occur in searching,
and sublinear performance O(HAYSTACK_LEN / NEEDLE_LEN) is possible.
If AVAILABLE modifies HAYSTACK_LEN (as in strstr), then at most 3 *
HAYSTACK_LEN - NEEDLE_LEN comparisons occur in searching, and
sublinear performance is not possible. */
static RETURN_TYPE
two_way_long_needle (const unsigned char *haystack, size_t haystack_len,
const unsigned char *needle, size_t needle_len)
{
size_t i; /* Index into current byte of NEEDLE. */
size_t j; /* Index into current window of HAYSTACK. */
size_t period; /* The period of the right half of needle. */
size_t suffix; /* The index of the right half of needle. */
size_t shift_table[1U << CHAR_BIT]; /* See below. */
/* Factor the needle into two halves, such that the left half is
smaller than the global period, and the right half is
periodic (with a period as large as NEEDLE_LEN - suffix). */
suffix = critical_factorization (needle, needle_len, &period);
/* Populate shift_table. For each possible byte value c,
shift_table[c] is the distance from the last occurrence of c to
the end of NEEDLE, or NEEDLE_LEN if c is absent from the NEEDLE.
shift_table[NEEDLE[NEEDLE_LEN - 1]] contains the only 0. */
for (i = 0; i < 1U << CHAR_BIT; i++)
shift_table[i] = needle_len;
for (i = 0; i < needle_len; i++)
shift_table[CANON_ELEMENT (needle[i])] = needle_len - i - 1;
/* Perform the search. Each iteration compares the right half
first. */
if (CMP_FUNC (needle, needle + period, suffix) == 0)
{
/* Entire needle is periodic; a mismatch in the left half can
only advance by the period, so use memory to avoid rescanning
known occurrences of the period in the right half. */
size_t memory = 0;
size_t shift;
j = 0;
while (AVAILABLE (haystack, haystack_len, j, needle_len))
{
/* Check the last byte first; if it does not match, then
shift to the next possible match location. */
shift = shift_table[CANON_ELEMENT (haystack[j + needle_len - 1])];
if (0 < shift)
{
if (memory && shift < period)
{
/* Since needle is periodic, but the last period has
a byte out of place, there can be no match until
after the mismatch. */
shift = needle_len - period;
}
memory = 0;
j += shift;
continue;
}
/* Scan for matches in right half. The last byte has
already been matched, by virtue of the shift table. */
i = MAX (suffix, memory);
while (i < needle_len - 1 && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
++i;
if (needle_len - 1 <= i)
{
/* Scan for matches in left half. */
i = suffix - 1;
while (memory < i + 1 && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
--i;
if (i + 1 < memory + 1)
return (RETURN_TYPE) (haystack + j);
/* No match, so remember how many repetitions of period
on the right half were scanned. */
j += period;
memory = needle_len - period;
}
else
{
j += i - suffix + 1;
memory = 0;
}
}
}
else
{
/* The two halves of needle are distinct; no extra memory is
required, and any mismatch results in a maximal shift. */
size_t shift;
period = MAX (suffix, needle_len - suffix) + 1;
j = 0;
while (AVAILABLE (haystack, haystack_len, j, needle_len))
{
/* Check the last byte first; if it does not match, then
shift to the next possible match location. */
shift = shift_table[CANON_ELEMENT (haystack[j + needle_len - 1])];
if (0 < shift)
{
j += shift;
continue;
}
/* Scan for matches in right half. The last byte has
already been matched, by virtue of the shift table. */
i = suffix;
while (i < needle_len - 1 && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
++i;
if (needle_len - 1 <= i)
{
/* Scan for matches in left half. */
i = suffix - 1;
while (i != SIZE_MAX && (CANON_ELEMENT (needle[i])
== CANON_ELEMENT (haystack[i + j])))
--i;
if (i == SIZE_MAX)
return (RETURN_TYPE) (haystack + j);
j += period;
}
else
j += i - suffix + 1;
}
}
return NULL;
}
#undef AVAILABLE
#undef CANON_ELEMENT
#undef CMP_FUNC
#undef MAX
#undef RETURN_TYPE

22
m4/gnulib-comp.m4
View file

@ -113,6 +113,7 @@ AC_DEFUN([gl_EARLY],
# Code from module localtime-buffer:
# Code from module lstat:
# Code from module manywarnings:
# Code from module memmem-simple:
# Code from module memrchr:
# Code from module minmax:
# Code from module mkostemp:
@ -195,6 +196,7 @@ AC_DEFUN([gl_INIT],
gl_source_base='lib'
gl_FUNC_ACL
gl_FUNC_ALLOCA
gl___BUILTIN_EXPECT
gl_BYTESWAP
AC_CHECK_FUNCS_ONCE([readlinkat])
gl_CLOCK_TIME
@ -302,6 +304,11 @@ AC_DEFUN([gl_INIT],
gl_PREREQ_LSTAT
fi
gl_SYS_STAT_MODULE_INDICATOR([lstat])
gl_FUNC_MEMMEM_SIMPLE
if test $HAVE_MEMMEM = 0 || test $REPLACE_MEMMEM = 1; then
AC_LIBOBJ([memmem])
fi
gl_STRING_MODULE_INDICATOR([memmem])
gl_FUNC_MEMRCHR
if test $ac_cv_func_memrchr = no; then
AC_LIBOBJ([memrchr])
@ -426,7 +433,6 @@ AC_DEFUN([gl_INIT],
gl_UTIMENS
AC_C_VARARRAYS
gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b=false
gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547=false
gl_gnulib_enabled_cloexec=false
gl_gnulib_enabled_dirfd=false
gl_gnulib_enabled_euidaccess=false
@ -450,13 +456,6 @@ AC_DEFUN([gl_INIT],
func_gl_gnulib_m4code_open
fi
}
func_gl_gnulib_m4code_37f71b604aa9c54446783d80f42fe547 ()
{
if ! $gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547; then
gl___BUILTIN_EXPECT
gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547=true
fi
}
func_gl_gnulib_m4code_cloexec ()
{
if ! $gl_gnulib_enabled_cloexec; then
@ -652,9 +651,6 @@ AC_DEFUN([gl_INIT],
if test $HAVE_READLINKAT = 0; then
func_gl_gnulib_m4code_03e0aaad4cb89ca757653bd367a6ccb7
fi
if test $ac_use_included_regex = yes; then
func_gl_gnulib_m4code_37f71b604aa9c54446783d80f42fe547
fi
if test $ac_use_included_regex = yes; then
func_gl_gnulib_m4code_21ee726a3540c09237a8e70c0baf7467
fi
@ -666,7 +662,6 @@ AC_DEFUN([gl_INIT],
fi
m4_pattern_allow([^gl_GNULIB_ENABLED_])
AM_CONDITIONAL([gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b], [$gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b])
AM_CONDITIONAL([gl_GNULIB_ENABLED_37f71b604aa9c54446783d80f42fe547], [$gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547])
AM_CONDITIONAL([gl_GNULIB_ENABLED_cloexec], [$gl_gnulib_enabled_cloexec])
AM_CONDITIONAL([gl_GNULIB_ENABLED_dirfd], [$gl_gnulib_enabled_dirfd])
AM_CONDITIONAL([gl_GNULIB_ENABLED_euidaccess], [$gl_gnulib_enabled_euidaccess])
@ -916,6 +911,7 @@ AC_DEFUN([gl_FILE_LIST], [
lib/lstat.c
lib/md5.c
lib/md5.h
lib/memmem.c
lib/memrchr.c
lib/minmax.h
lib/mkostemp.c
@ -959,6 +955,7 @@ AC_DEFUN([gl_FILE_LIST], [
lib/stdio.in.h
lib/stdlib.in.h
lib/stpcpy.c
lib/str-two-way.h
lib/strftime.h
lib/string.in.h
lib/strtoimax.c
@ -1049,6 +1046,7 @@ AC_DEFUN([gl_FILE_LIST], [
m4/manywarnings.m4
m4/mbstate_t.m4
m4/md5.m4
m4/memmem.m4
m4/memrchr.m4
m4/minmax.m4
m4/mkostemp.m4

154
m4/memmem.m4 Normal file
View file

@ -0,0 +1,154 @@
# memmem.m4 serial 25
dnl Copyright (C) 2002-2004, 2007-2019 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl Check that memmem is present and functional.
AC_DEFUN([gl_FUNC_MEMMEM_SIMPLE],
[
dnl Persuade glibc <string.h> to declare memmem().
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
AC_CHECK_FUNCS([memmem])
if test $ac_cv_func_memmem = yes; then
HAVE_MEMMEM=1
else
HAVE_MEMMEM=0
fi
AC_CHECK_DECLS_ONCE([memmem])
if test $ac_cv_have_decl_memmem = no; then
HAVE_DECL_MEMMEM=0
else
dnl Detect https://sourceware.org/bugzilla/show_bug.cgi?id=12092.
dnl Also check that we handle empty needles correctly.
AC_CACHE_CHECK([whether memmem works],
[gl_cv_func_memmem_works_always],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <string.h> /* for memmem */
#define P "_EF_BF_BD"
#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
#define NEEDLE P P P P P
]], [[
int result = 0;
if (memmem (HAYSTACK, strlen (HAYSTACK), NEEDLE, strlen (NEEDLE)))
result |= 1;
/* Check for empty needle behavior. */
{
const char *haystack = "AAA";
if (memmem (haystack, 3, NULL, 0) != haystack)
result |= 2;
}
return result;
]])],
[gl_cv_func_memmem_works_always=yes],
[gl_cv_func_memmem_works_always=no],
[dnl glibc 2.9..2.12 and cygwin 1.7.7 have issue #12092 above.
dnl Also empty needles work on glibc >= 2.1 and cygwin >= 1.7.0.
dnl uClibc is not affected, since it uses different source code.
dnl Assume that it works on all other platforms (even if not linear).
AC_EGREP_CPP([Lucky user],
[
#ifdef __GNU_LIBRARY__
#include <features.h>
#if ((__GLIBC__ == 2 && ((__GLIBC_MINOR > 0 && __GLIBC_MINOR__ < 9) \
|| __GLIBC_MINOR__ > 12)) \
|| (__GLIBC__ > 2)) \
|| defined __UCLIBC__
Lucky user
#endif
#elif defined __CYGWIN__
#include <cygwin/version.h>
#if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
Lucky user
#endif
#else
Lucky user
#endif
],
[gl_cv_func_memmem_works_always="guessing yes"],
[gl_cv_func_memmem_works_always="guessing no"])
])
])
case "$gl_cv_func_memmem_works_always" in
*yes) ;;
*)
REPLACE_MEMMEM=1
;;
esac
fi
gl_PREREQ_MEMMEM
]) # gl_FUNC_MEMMEM_SIMPLE
dnl Additionally, check that memmem has linear performance characteristics
AC_DEFUN([gl_FUNC_MEMMEM],
[
AC_REQUIRE([gl_FUNC_MEMMEM_SIMPLE])
if test $HAVE_DECL_MEMMEM = 1 && test $REPLACE_MEMMEM = 0; then
AC_CACHE_CHECK([whether memmem works in linear time],
[gl_cv_func_memmem_works_fast],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <signal.h> /* for signal */
#include <string.h> /* for memmem */
#include <stdlib.h> /* for malloc */
#include <unistd.h> /* for alarm */
static void quit (int sig) { _exit (sig + 128); }
]], [[
int result = 0;
size_t m = 1000000;
char *haystack = (char *) malloc (2 * m + 1);
char *needle = (char *) malloc (m + 1);
/* Failure to compile this test due to missing alarm is okay,
since all such platforms (mingw) also lack memmem. */
signal (SIGALRM, quit);
alarm (5);
/* Check for quadratic performance. */
if (haystack && needle)
{
memset (haystack, 'A', 2 * m);
haystack[2 * m] = 'B';
memset (needle, 'A', m);
needle[m] = 'B';
if (!memmem (haystack, 2 * m + 1, needle, m + 1))
result |= 1;
}
/* Free allocated memory, in case some sanitizer is watching. */
free (haystack);
free (needle);
return result;
]])],
[gl_cv_func_memmem_works_fast=yes], [gl_cv_func_memmem_works_fast=no],
[dnl Only glibc >= 2.9 and cygwin > 1.7.0 are known to have a
dnl memmem that works in linear time.
AC_EGREP_CPP([Lucky user],
[
#include <features.h>
#ifdef __GNU_LIBRARY__
#if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)) \
&& !defined __UCLIBC__
Lucky user
#endif
#endif
#ifdef __CYGWIN__
#include <cygwin/version.h>
#if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 0)
Lucky user
#endif
#endif
],
[gl_cv_func_memmem_works_fast="guessing yes"],
[gl_cv_func_memmem_works_fast="guessing no"])
])
])
case "$gl_cv_func_memmem_works_fast" in
*yes) ;;
*)
REPLACE_MEMMEM=1
;;
esac
fi
]) # gl_FUNC_MEMMEM
# Prerequisites of lib/memmem.c.
AC_DEFUN([gl_PREREQ_MEMMEM], [:])

30
src/Makefile.in
View file

@ -332,6 +332,7 @@ UNEXEC_OBJ = @UNEXEC_OBJ@
DUMPING=@DUMPING@
CHECK_STRUCTS = @CHECK_STRUCTS@
HAVE_PDUMPER = @HAVE_PDUMPER@
# 'make' verbosity.
AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
@ -627,19 +628,25 @@ LIBEGNU_ARCHIVE = $(lib)/lib$(if $(HYBRID_MALLOC),e)gnu.a
$(LIBEGNU_ARCHIVE): $(config_h)
$(MAKE) -C $(dir $@) all
FINGERPRINTED = $(LIBXMENU) $(ALLOBJS) $(LIBEGNU_ARCHIVE) $(EMACSRES)
fingerprint.c: $(FINGERPRINTED) $(libsrc)/make-fingerprint$(EXEEXT)
$(AM_V_GEN)$(libsrc)/make-fingerprint$(EXEEXT) $(FINGERPRINTED) >$@.tmp
$(AM_V_at)mv $@.tmp $@
ifeq ($(HAVE_PDUMPER),yes)
MAKE_PDUMPER_FINGERPRINT = $(libsrc)/make-fingerprint$(EXEEXT)
else
MAKE_PDUMPER_FINGERPRINT =
endif
## We have to create $(etc) here because init_cmdargs tests its
## existence when setting Vinstallation_directory (FIXME?).
## This goes on to affect various things, and the emacs binary fails
## to start if Vinstallation_directory has the wrong value.
temacs$(EXEEXT): fingerprint.o $(charsets) $(charscript)
$(AM_V_CCLD)$(CC) -o $@ $(ALL_CFLAGS) $(TEMACS_LDFLAGS) $(LDFLAGS) \
$(ALLOBJS) fingerprint.o \
$(LIBEGNU_ARCHIVE) $(W32_RES_LINK) $(LIBES)
temacs$(EXEEXT): $(LIBXMENU) $(ALLOBJS) $(LIBEGNU_ARCHIVE) $(EMACSRES) \
$(charsets) $(charscript) $(MAKE_PDUMPER_FINGERPRINT)
$(AM_V_CCLD)$(CC) -o $@.tmp \
$(ALL_CFLAGS) $(TEMACS_LDFLAGS) $(LDFLAGS) \
$(ALLOBJS) $(LIBEGNU_ARCHIVE) $(W32_RES_LINK) $(LIBES)
ifeq ($(HAVE_PDUMPER),yes)
$(AM_V_at)$(MAKE_PDUMPER_FINGERPRINT) $@.tmp
endif
$(AM_V_at)mv $@.tmp $@
$(MKDIR_P) $(etc)
ifeq ($(DUMPING),unexec)
ifneq ($(PAXCTL_notdumped),)
@ -676,7 +683,7 @@ ns-app: emacs$(EXEEXT) $(pdmp)
mostlyclean:
rm -f temacs$(EXEEXT) core ./*.core \#* ./*.o
rm -f dmpstruct.h fingerprint.c
rm -f dmpstruct.h
rm -f emacs.pdmp
rm -f ../etc/DOC
rm -f bootstrap-emacs$(EXEEXT) $(bootstrap_pdmp)
@ -716,10 +723,9 @@ ETAGS = ../lib-src/etags${EXEEXT}
${ETAGS}: FORCE
$(MAKE) -C $(dir $@) $(notdir $@)
# Remove macuvs.h and fingerprint.c since they'd cause `src/emacs`
# Remove macuvs.h since it'd cause `src/emacs`
# to be built before we can get TAGS.
ctagsfiles1 = $(filter-out ${srcdir}/macuvs.h ${srcdir}/fingerprint.c, \
$(wildcard ${srcdir}/*.[hc]))
ctagsfiles1 = $(filter-out ${srcdir}/macuvs.h, $(wildcard ${srcdir}/*.[hc]))
ctagsfiles2 = $(wildcard ${srcdir}/*.m)
## In out-of-tree builds, TAGS are generated in the build dir, like